Installation of Tubewells

After completion of a bore hole to the desired length, the tubewell assembly is to be lowered and fixed in position as soon as possible. The bore hole is usually drilled a little more than the installed depth of the tubewell to accommodate the materials which may cave in or settle in the bore hole before installation of the tubewell. The sand trap, strainers, blind pipes, housing pipes, etc are assembled near the tubewell and marked serially. The components of the tubewell are than lowered one by one as required starting from the bottom end. Each component of the tubewell is to be properly screwed or welded to another and slowly lowered vertically with the help of clamps. When the lowering of the tubewell is complete, it is kept suspended from the top of the bore hole and clean sand or properly designed cleaned shrouding gravel is dropped in the bore hole. The coarse sand or shrouding material is filled to at least 10 to 15 m above the top of the upper strainer. These materials grip the strainers and the blind pipes on the out side and hold the tubewell in position. The remaining space of the bore hole may be filled with clayey materials to prevent percolation of contaminated water from the surface.

It is important that the entire tubewell is installed straight and vertical. In case of large diameter tubewells, guides are placed at a certain distance apart for concentric installation, to permit uniform filing of shrouding materials around the well and satisfactory operation of the pumping unit and without damage.